Much has changed at Cecil Airport since the Navy left and Jacksonville Aviation Authority took over, but one sight has remained the same — the thick stand of forest lining the runways on the east side of the airport.

Now the aviation authority is moving ahead with plans to open a 120-acre tract of woods for development by building a three-lane road and a taxiway.

“When you see all the pine trees over there, those pine trees will come out and we’ll develop it with new hangars,” Bob Simpson, interim chief operating officer, said Thursday.

About 2,500 people work at Cecil Airport, whether it’s for private companies or government agencies. Additional job growth is bumping up against limits of existing hangars, which are fully leased.

The authority plans to build two new hangars — a 30,000-square-foot building and another at 15,000 square feet — in the coming months next to existing hangars where parcels are available for new structure. But the next phase of expansion will shift toward the wooded area on the opposite side of the airport, giving the authority more room for larger hangars. A $3 million three-lane road from 103rd Street could start construction by the end of the year. The taxiway, costing $6 million to $7 million, could break ground in early 2012.

Simpson discussed the upcoming work with reporters during a media tour of Cecil Airport, which was known as Cecil Field when it was a Navy base. After the federal government closed the base, the Navy turned over 800,000 square feet of hangars and 310,000 square feet of office buildings to the aviation authority. In the past 12 years, the aviation authority has added 292,000 square feet of hangars.

Simpson said the pace of future growth will depend on factors such as the strength of the overall economy and the availability of Department of Defense contracts.

“We swing with the economy,” he said. “The good news at Cecil is we have a real good mix of government and commercial” tenants.

The latest addition is a 100,000-square-foot hangar jointly used by Florida State College at Jacksonville and FlightStar. The college offers courses in airplane painting at the hangar. FlightStar, which also leases another hangar, has expanded its contracts with companies such as AirTran and Federal Express. It has grown to 575 employees at Cecil Airport.

FlightStar Chief Operating Officer Tucker Morrison said the company can probably grow by another 15 percent before it would need additional hangar space. As the economy improves, airplanes will log more miles carrying people and cargo, and that in turn will necessitate additional plane maintenance, he said.

Cecil Airport’s aircraft maintenance business will expand to cover corporate jets when KCI Enterprises, based in West Virginia, moves into a 30,000-square-foot hangar the authority plans to build. Last month, the Jacksonville City Council approved a $165,000 package of city and state financial incentives for KCI, contingent on the company creating 30 jobs by the end of 2014.